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Prognosis of Patients With Advanced Idiopathic Pulmonary Fibrosis Requiring Mechanical Ventilation for Acute Respiratory Failure: LTx

Prognosis of Patients With Advanced Idiopathic Pulmonary Fibrosis Requiring Mechanical Ventilation for Acute Respiratory Failure: LTxLTx has now gained widespread acceptance as a therapeutic option in patients with IPF. Moreover, it has been recently shown that LTx confers a survival benefit in patients with IPF compared with spontaneous survival on waiting lists. Performing LTx in IPF ventilator-dependent patients raises difficult issues. It has been demonstrated that performing LTx in a ventilator-dependent patient carries a significantly increased risk of death during the first year after transplantation. Nevertheless, it has been shown that ventilator-dependent patients with various diseases including COPD or IPF can undergo successful LTx provided they are carefully select-ed. In particular, short periods of ventilation and absence of organ dysfunction other than their respiratory failure are required. It is thus conceivable to initiate MV in IPF patients who are already on waiting lists and who develop ARF. In those who are not already on a waiting list, the probability of transplantation is very low in France given the current scarcity of donor lungs as well as the absence of effective processes to expedite LTx in urgent situations. This point is illustrated by our series where among the 16 patients evaluated for the feasibility of LTx, only 5 patients were already enrolled on the waiting list and only 1 of these 5 patients underwent LTx. The unpredictable course of IPF should encourage chest physicians to refer IPF patients to transplantation centers early in the course of their disease according to the recently published guidelines for selection of lung transplant candidates. Despite the increased risk of perioperative death in ventilator-dependent patients who undergo LTx, we believe that IPF patients who are already on waiting lists should have priority for the allocation of a graft when they develop ARF and require MV.
Alteration of static compliance is well documented in IPF, and a study by Nava and Rubini indicates that end-stage IPF patients have major alteration of lung mechanics during MV. In particular, markedly elevated levels of pulmonary elastance and total lung resistance were found. The authors also described that dynamic and static elastance of the respiratory system as well as total respiratory resistance correlated positively with the degree of PaC02 recorded just before intubation. These alterations are thought to be mostly due to the inflammatory and fibrosing process that progressively involve the lungs. Because the design of our study was retrospective, the data on lung and chest mechanics in patients receiving MV were not available. In our study, the correlations between baseline TLC (percent predicted), VC (percent predicted), baseline PaC02, and the duration of MV are in accordance with the data of Nava and Rubini.
In conclusion, in patients with end-stage pulmonary fibrosis presenting with ARF, the precipitating cause is most often not identified. Moreover, our data support the general belief that MV does not benefit these patients. Initiation of MV in IPF patients is thus questionable. We believe that it should be restricted to patients in whom LTx can be performed within a few days after initiation of MV.